The use of nozzles to promote chemical reactions is old in the art. Nozzles have been designed to accomplish a variety of mixing and atomization tasks with a large variety of fluids and gases. The mixing and/or atomization in conventional nozzles is usually accomplished by a forceful uniting of the liquids and gases either internally in a mixing chamber or externally by directing the liquids into each other's pathway. Where the mixing and atomization is to be accomplished internally, as in a mixing chamber, the nozzle is usually designed to facilitate the forceful joining of the fluids in order to induce a sudden high turbulence.
For example, U.S. Pat. No. 3,764,069 issued to P. W. Runstadler, Jr. on Oct. 9, 1973 discloses a method and apparatus for atomizing and spraying liquids. The liquid to be sprayed is supplied under a pressure of from 2-7 atmospheres (gauge) through liquid passage 43 and is caused to flow in a thin film through annular flow passage 68. Streams of gas at a slightly higher pressure are impinged against the liquid film such that the air-to-liquid mass ratio is from 0.1 to 1.6 and such that the gas is sheared and broken up into microbubbles which are entrained in the liquid to form a froth. The mixture is then directed through section 89 and through passageway 75 where the pressure decreases gradually so that the bubbles tend to expand slightly, thereby tending to make the froth mixture become more homogeneous. The mixture is then discharged through nozzle orifice 78 whereupon the air bubbles explode, rupturing the liquid film and causing the liquid to disintegrate into finely atomized drops.
U.S. Pat. No. 3,719,325 issued to A. Cerva et al. on Mar. 6, 1973 discloses a nozzle for a pneumatic-hydraulic head for cleaning of molds for pressure casting of metal and depositing a layer of separating material on the mold surface. The nozzle comprises a nozzle head 1 having a central passageway 7, an annular passageway 9 and a chamber 10, a nozzle body 2 centrally located in chamber 10 such that there is a narrow annular passageway between the inner wall of chamber 10 and the outer wall of body 2 and having a central passageway 4 that connects with passageway 7, and hood 6 having a swirl chamber 12 and discharge orifice 8. Pressurized air is directed through passageway 9 and chamber 10 into spiral-shaped mixing channel 11 that is formed between part of the inner wall of hood 6 and part of the outer wall of body 2. The liquid separating material is directed through passageways 7 and 4 and then via transfer channel 5 into mixing channel 11 where it is thoroughly mixed with the air. The mixture is then swirled through chamber 12, which causes the separating material to be atomized, and the mixture is then discharged through orifice 8.
A slightly different approach to the mixing and atomizing of liquids and gases might make use of both internal and external contacting of the fluids for complete mixing and atomization. For example, U.S. Pat. No. 1,995,934 issued to W. B. Mangold on Mar. 26, 1935 discloses a gas burner having several concentric channels for feeding several different fluids. A central passageway 10 is for air only. The surrounding shorter annular passageway 24 is for gas and it mixes internally with air from a third passageway 14 which surrounds passageway 24. The mixing of the gas from passageway 24 and air from passageway 14 is further facilitated by double conical screen 28. Two additional annular passageways for air which surround passageway 15, direct additional streams of air to the burner exit where the unmixed air mixes with the air and gas mixture exiting from passageway 15.
Yet another approach to mixing and atomizing employs several nozzles that are mounted one inside the other such that mixing occurs at the several points where the nozzles discharge into the next succeeding nozzle. For example, U.S. Pat. No. 3,717,306 issued to J. R. Hushon et al. discloses a nozzles for spraying foaming materials. The nozzle comprises two concentric nozzle members. One material 18 flows through the central nozzle via the concentric channel 12, tangentially into the central annular space 13 which causes it to swirl as it flows through outlet end 10. The second material 16 flows through the annular chamber 15, and into space 28 via the tangentially disposed openings 29 which causes it to swirl as it empties, along with the first material, into space 30 where the materials are mixed and reacted to form the foam product.
A further method for mixing and atomizing involves externally mixing the several materials. For example, U.S. Pat. No. 3,929,291 issued to G. Ladisch on Dec. 30, 1975 discloses a spray mixing nozzle for reacting acid and base. The nozzle comprises a central pressurized gas channel 1, at least two surrounding annular channels 2 and 3 for acid and base and an outer annular channel for pressurized gas. The discharge outlet of the outer annular channel tapers conically and discharges the pressurized gas in a converging direction to thereby force the acid and base against the central air discharge and forcefully mix and atomize the acid and base so that they will react. The ratio of the throughflow diameters for the pressure gas in the central pressure gas channel and in the outer annular gas channel is preferably in a ratio of from 1:3 to 1:10. The nozzle also includes a water spray nozzle 12 that directs a stream of water against the spray mixing nozzle to prevent a buildup of a crust that can frequently form when spraying highly concentrated acids with concentrated alkali solutions. A divisional case, now U.S. Pat. No. 4,022,379 which issued to G. Ladisch et al. on May 10, 1977, discloses the identical spray mixing nozzle without the water nozzle 12.
Canadian Pat. No. 880,212, which issued to O. Pfrengle on Apr. 22, 1970, discloses a process for reacting a basic liquid phase with an acidic liquid phase and an air pressure mixing nozzle for carrying out the similar neutralization process. The nozzle is similar to the above-described Ladisch patent and comprises two concentric canals or ducts surrounding a central bore. The acidic liquid and the basic liquid are passed through the central bore and the inner of the two concentric canals. Compressed air between about 1 and about 4 atmospheres, gauge, is passed through the outer canal. The discharge exits from the two concentric canals are generally conically tapered so that the liquids and gas will impinge on one another. The liquids are atomized by the air pressure and are substantially mixed immediately after leaving the nozzle and any unmixed portion is mixed within a distance beyond the nozzle of from about 300 to 800 centimeters. Upon mixing, the acid and base react to form a highly viscous product.
The above-described art discloses a wide variety of nozzles and methods for atomizing and mixing several fluids and gases. However, whenever there has been a need to combine several materials that will react with one another and that will produce a highly viscous material such as the acid and base mixing described in Ladisch and the urethane foam of Heshon et al. the procedure is normally to externally atomize and/or mix the materials to avoid having to deal with either a developing reaction and controlling it or a thick material that may tend to clog the nozzle. The atomization and mixing of an acidic liquid such as an organic acid with long carbon chains and a concentrated basic liquid are prime examples of materials that are handled using this approach. However, the use of external mixing is both inefficient and energy intensive. On the other hand, the more preferred process (high energy transfer) of internal mixing has heretofore not been successfully employed for the acid and base reaction or, for that matter, for handling the mixing of those materials where the final product was highly viscous.
Accordingly, an object of this invention is to provide a method and apparatus for atomizing and mixing liquids and/or gases internally in the apparatus.
A further object of this invention is to provide a new method and apparatus for effecting and controlling a chemical reaction between the liquids and/or gases that have been mixed and atomized, internally in the apparatus to form a powdery or highly viscous product.
A still further object of the invention is to provide a process for effecting a chemical reaction and for atomizing and mixing several liquids and/or gases that is both efficient and uses a minimum of energy.